1. FIELD OF THE INVENTION
The present invention relates to a fuel injection system for a diesel engine including a unit injector which is mounted in a cylinder head and which is integrally provided with a pump section for supplying a fuel and a nozzle section for injecting the fuel supplied from the pump section into a cylinder.
2. DESCRIPTION OF THE PRIOR ART
A known fuel injection system for a diesel engine including a unit injector is described in Japanese Patent Publication Laid-open No. 533378/88.
In the unit injector described in the above Patent, the pump and nozzle sections are integrally formed such that their axes are aligned with each other. The unit injector is mounted in the cylinder head such that the entire unit injector is inclined with respect to an axis of the cylinder.
If the unit injector is mounted to the cylinder head in the inclined attitude as in the above prior art system, an upper end of the unit injector protrudes sideways, and as a result, the lateral width of the cylinder head is increased, but also a nozzle hole is uneven due to the inclination of the nozzle section and hence, the spray of the fuel into a combustion chamber within the cylinder is non-uniform. When the unit injector is mounted to the cylinder head in an upright attitude in order to avoid this, if the numbers of intake and exhaust valves are increased, there is encountered a problem that the unit injector interferes with valve springs, resulting in a difficult layout. There is also a problem that the unit injector largely protrudes upwardly, resulting in an increased size of the cylinder head.